Polycarbonate and process for producing the same

Abstract

A polycarbonate containing an ether diol residue producible from a polysaccharide and expressed by the following formula (1), and a diol residue expressed by the following formula (2) —O—(C m H 2m )—O—   (2) (here, m is an integer of 2 to 12), wherein said ether diol residue amounts to 65-98 wt. % of all the diol residues, and having a glass transition temperature of 90° C. or higher.

1. A polycarbonate containing an ether diol residue producible from a polysaccharide and expressed by the following formula (1), 
       
         
           
           
               
               
           
         
       
       and a diol residue expressed by the following formula (2)
   —O—(C m H 2m )—O—  (2) 
 
       (here, m is an integer selected from 2, 3 and 6), wherein said ether diol residue amounts to 65-98 wt. % of all the diol residues, and having a glass transition temperature of 100 to 160° C. 
     
     
       2. The polycarbonate according to  claim 1  containing at least two kinds of the diol residues expressed by the formula (2). 
     
     
       3. The polycarbonate according to  claim 1  containing the isosorbide residue as the ether diol residue. 
     
     
       4. The polycarbonate according to  claim 3 , wherein the isosorbide residue amounts to 65 to 98 wt. % of all the diol residues. 
     
     
       5. A method for producing the polycarbonate according to  claim 1 , wherein the polycarbonate is produced from an ether diol expressed by the following formula (3), 
       
         
           
           
               
               
           
         
       
       a diol expressed by the following formula (4)
   HO—(C m H 2m )—OH  (4) 
 
       (here, m is an integer selected from 2, 3 and 6) and a carbonic acid diester by a melt polymerization method. 
     
     
       6. The polycarbonate-producing method according to  claim 5 , wherein an ether diol expressed by the above-mentioned formula (3), a diol expressed by the above-mentioned formula (4) and a carbonic acid diester are subjected to a thermal reaction at atmospheric pressure in the presence of polymerization catalysts, and subsequently the reaction product is subjected to melt polycondensation under reduced pressure while heated at a temperature in the range of 180° C. to 280° C. 
     
     
       7. The polycarbonate-producing method according to  claim 6 , wherein at least one compound selected from the group consisting of nitrogen-containing basic compounds, alkali metal compounds and alkaline earth metal compounds is used as the polymerization catalysts. 
     
     
       8. The polycarbonate-producing method according to  claim 7 , wherein tetramethylammonium hydroxide and 2,2-bis(4-hydroxyphenyl)propane disodium salt are used as the polymerization catalysts. 
     
     
       9. The polycarbonate-producing method according to  claim 5 , wherein diphenyl carbonate is used as the carbonic acid diester.